Kathryn Schulz recently suggested that Henry David Thoreau and his most famous book, “Walden,” are not worth their place as classics of American philosophy and writing. In her article in The New Yorker (“Pond Scum: Henry David Thoreau’s Moral Myopia”), she made some well-worn, if sometimes misleading, points — namely that Thoreau was conceited, contradictory, hypocritical, and perhaps worst of all in Schulz’s eyes, he did not like people or society. She pokes holes in the modern “myths” of Thoreau and “Walden,” which don’t match historical reality. Her article makes for a fun read, but it is decidedly one-sided.
In point of fact, most people are unaware of just how timeless Thoreau’s legacy is — how it continues to be relevant for issues such as the loss of species, excessive materialism and consumer culture, and the value of higher education. His writings are even (or especially) relevant for more recent issues such as climate change, which were not issues at all in Thoreau’s time. In some ways, the modern myth of Thoreau doesn’t do the author justice.
Everyone knows that Thoreau was an unusually perceptive observer of nature who wrote eloquently and passionately about the need to preserve wild spaces. He also kept a voluminous journal — 2 million words by the time he passed away. But few know about his detailed notes on the emergence of leaves and flowers on hundreds of plant species and the arrival of migratory birds and the departure of ice on Walden Pond. These notes were so overlooked that the editors who first published his journals cut them to save space; they were left as scraps on the editing room floor as it were.

Thoreau recognized their value. He pulled the observations from his journals and created neatly organized tables (well, sort of neat, except for his incredibly bad handwriting) listing the leaves, flowers, birds, and other natural events he saw on each day for eight years between 1851 and 1858. He was creating a nature calendar.
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These tables have been invaluable tools for investigating the impact of climate change on New England’s flora and fauna. His observations have been the foundation for a line of work and insights that has involved numerous students and researchers from many universities and countries and is still growing and expanding today.
The timing of many of the events that Thoreau noted — the days that blueberries flowered, yellow-rumped warblers arrived, or ice melted on Walden Pond — are exquisitely sensitive to changes in temperature. They reveal that because of warming temperatures in Concord (warming associated with human-induced climate change) many plants now flower and leaf out about 10 days earlier than in Thoreau’s time. Warming temperatures have also contributed to the decline of many of our most treasured wildflowers in Concord — think lilies and orchids — and have facilitated the spread of invasive species such as purple loosestrife.
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The varied ways in which different species respond to a warming climate is also changing the ways in which species interact. Most notably, plants and insects, such as butterflies and bees, are more responsive to warm spring temperatures than are migratory birds, potentially disrupting relationships among them.
Thoreau himself saw this phenomenon and noted how weather conditions affected relationships among species. In his journal entry of April 23, 1852, for example, he described how late frosts damage leaf buds, in turn harming insects and birds.
Countless professional biologists and amateur naturalists around the country and the world have been inspired by Thoreau. Hundreds of thousands of citizen science volunteers walk in Thoreau’s footsteps and submit their observations of natural events, such as flowering and bird arrivals, to online databases. Not all of these people are aware of the connection to Thoreau, of course, but the value of these observations for science and society — whatever the motivation of those who gather them — is difficult to overstate.
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In her essay, Schulz sought to bring a saint of American history down a peg. Instead he deserves to be raised a peg. Even for all his foibles and faults, Thoreau’s contributions to writing, science, and society are worth celebrating. Observe nature carefully. Live simply. Be engaged civically. If Thoreau were alive today, perhaps he would even be fighting to end the activities that contribute to our changing climate.
Richard B. Primack is a professor at Boston University and author of “Walden Warming: Climate change comes to Thoreau’s Woods.” Abraham J. Miller-Rushing is an adjunct researcher at the University of Maine.